I know I'm kind of late to this discussion but I would like to chime in here if I can.
I think that if the picture quality of TNG could be improved I would be for a remastered version but not necessarily to see sfx replaced. All I would care for is a "cleaner" picture. However, from what I understand the original tape source is the real problem and it is unlikely TNG will get remastered because of that reason.
I am not for replacing CGI effects and such as I think that the show does and should stand on it's own. What if someone had wanted to redo all the sfx in the three Flash Gordon serials from the 1930's? I think it would be an outrage! The main thing to me is not how cool and updated the sfx are but do they help tell the "story"? Yes...it's the story that is important and all this modern day crap about improving the sfx etc. does nothing for the "story". TNG is a product of it's "time". Just as Flash Gordon was a product of it's time. I say leave the work alone! It's like someone thinking they could improve a Rembrandt for crying out loud! Now that I'd like to see! (He says sarcastically)
While I doubt there is any call for it, 1930s FX COULD be replaced if it were done with a 30s feel and if it matched the era, much in the way TOS-R had muted FX instead of Enterprise quality work.
Actually FX CAN improve story-TELLING if the new images can make the script payoff....TOS-R's Galileo 7 for example. But if you can improve ONE element out of all that go into production (ie: sound, visuals, lighting, cinematography, etc) then why not.